This invention relates to agitators for mixing tanks and the like, and while the invention is subject to a wide range of applications, a preferred embodiment of the invention will be particularly described as applied to an agitator having a detachable wear sleeve secured on its shaft.
In the use of agitators in mixing tanks, and the like, an impeller is projected into the tank, having its operating shaft, motor, and bearings external of the tank and sealed from the tank contents by a mounting flange, in combination with shaft sealing means such as a stuffing box, and the like. Various systems have been devised for service of the agitator bearings and stuffing box, including the use of a valve operable to seal the agitator shaft temporarily during such servicing operations to prevent the escapement of fluid around the agitator shaft from the tank under these conditions, and thus obviate any necessity of interfering with processes involving the contents of the tank during servicing operations. One such valve is disclosed in the DYKMAN U.S. Pat. No. 2,945,711, while a system for replacement of the bearings and of the packing of a stuffing box around the shaft is disclosed, for example, in the BOUTROS U.S. Pat. No. 2,612,391. In this patent, a stuffing box contains packing rings bearing directly upon an agitator shaft. The rings thus have a tendency to wear the shaft in time, providing possibility of leakage unless the shaft is replaced. Such replacement is costly, and may require a costly shutdown of a system in which the agitator is used. The replacement of the entire shaft can be avoided by using a wear sleeve secured on the shaft, as is disclosed in the BISSELL U.S. Pat. No. 2,137,328, but the system according to this patent requires removal of a pin inside the tank which locks the sleeve to the shaft. Thus the sleeve according to this patent could not be changed without performing operations within the tank, thus requiring a shut down of a system in which the agitator is operating.
An object of the present invention is to provide an agitator which substantially obviates one or more of the limitations and disadvantages of the described prior art systems.
Another object of the present invention is to provide an improved system for replacement of a wear sleeve on an agitator shaft.
Another object of the present invention is to provide an improved agitator assembly which materially reduces the cost of servicing.
Other objects, purposes and characteristic features of the present invention will be in part obvious from the accompaning drawings, and in part pointed out as the description of the invention progresses.